1. Field of the Invention
This invention relates to the use of higher alkyl modified epoxy silicones, which can be formed into emulsions, as a fiber finish. These silicone emulsions are applied to the fiber or a textile and are cured at relatively low temperatures.
2. Description of the Prior Art
Aqueous emulsions of epoxy-silicones have been used for textile fabrics using nonionic or anionic emulsifiers to prepare the water-dispersible emulsions.
Silicones are used as treatments for synthetic fibers to improve hand, loft and recovery from load. Silicone treated fiber is frequently used as filling for pillows, sleeping bags and comforters because of down-like aesthetics imparted by silicone finishing. Unreactive or nonsubstantive silicones such as dimethylsilicones are generally recognized as being unsuitable because of poor aesthetic properties and unacceptable durability after washing.
Crosslinking and substantivity of the finish on fiber surfaces is extremely critical in developing suitable properties for use as filling material (usually known in the trade as fiberfill). When crosslinking is effected, interfiber friction is reduced, which results in a nonscroopy fibrous assembly with a soft hand. The level of softness as qualitatively measured by hand correlates well with a numerical index of interfiber friction known as staple pad friction (SPF). Typically, crosslinking requires curing at 80.degree. C.-190.degree. C., although a few examples of curing at temperatures of 50.degree. or below have been noted.
In addition, crosslinking enhances durability to repeated home and commercial laundering. Finishes which are not crosslinked are readily removed from fiber surfaces, resulting in a harsh, scroopy assembly which has poor aesthetics. Although crosslinked finishes are more durable, most undergo a significant loss of desirable properties after five machine washings. Ideally, a finish would retain its original properties after repeated washings.
Current silicone finishes are generally applied to fiberfill as aqueous compositions and cured. In many cases, specially designed ovens which operate at high temperatures are required to achieve complete curing. Use of finishes that require curing under such conditions incurs several disadvantages. Excessively high cure temperature will result in high energy consumption and cost. But, more fundamentally, the properties imparted by these finishes are usually very sensitive to moderate changes in cure temperatures. As a result, nominal changes in process conditions result in significant changes in aesthetics and durability. Clearly, a highly desirable finish is one which develops consistent properties over a very broad range of process conditions.
In U.S. Ser. No. 537,670 filed Sept. 30, 1983, now abandoned, epoxyalkylsilicones are taught as gypsum paper sizes. Development of desirable properties at neutral pH without alum catalyst and curing at ambient temperature are claimed as novel advantages. Novel performance was attributed to an orientation effect which enhanced reaction with hydroxyl and carboxyl groups in cellulosic substrates such as paper. Although ambient curing is cited, it is extremely surprising and unobvious that use of these compounds on substrates such as polyester and polypropylene would result in low friction and durable surfaces without curing at elevated temperatures. The low concentration of reactive groups present on the surface of polyester and the absence of reactive groups in the case of polypropylene would suggest that direct reaction of epoxy groups with the substrate surface is highly unlikely.
In U.S. Ser. No. 480,701 filed Mar. 31, 1983, now U.S. Pat. No. 4,579,964, alkoxysilyl functional silicones are taught as useful in achieving desirable properties when applied and cured on textiles and fiberfill. Unusually good durability is cited as an unexpected advantage. However, U.S. Ser. No. 480,701 teaches that high durability is achieved only by effecting crosslinking in the presence of a catalyst such as p-toluene sulfonic acid. Examples of use suggest that best performance is obtained only by curing at elevated temperatures. No mention is made of attaining desirable properties by curing at room temperature.
In U.S. Pat. No. 3,251,794 (Paliyenko, Paul, et. al, May 17, 1966) the treatment of synthetic fiber filaments with mixture of dimethylsilicones and methylhydrogen-silicones to improve resilience and bulk is taught. Best performance was obtained by curing in the presence of zinc acetate/organic titanate catalysts at 150.degree. C. Attainment of desirable properties at ambient conditions is not indicated.
In U.S. Pat. No. 3,271,1989 (Hoffman, Hugo, Sept. 6, 1966) the use of crosslinkable mixtures of dimethylsilicones and methylhydrogensilicones as treatments for polyester fibers is taught. Examples indicate that best performance was obtained by curing at 132.degree. C. using a zinc catalyst. One example suggests that desirable properties could be attained at ambient conditions without catalysis. Teachings indicate that noncurable silicones are unsuitable for these uses. However, attempts to verify this effect proved unsuccessful.
In U.S. Pat. No. 3,639,154 (Soshio, S; et. al. Feb. 7, 1972) a process in which improved hand and water repellency are imparted to fibrous structures by treatment with mixtures of methylhydrogensilicones, dimethylsilicones, and polyethylene glycols was taught. Examples indicate that curing at 90.degree. C.-170.degree. C. and catalysis with zinc octoate is required to develop desirable properties.
In U.S. Pat. No. 3,953,651 (Sone, Masao, et al., Apr. 27, 1976) animal hairlike properties are imparted to acrylic fibers by treatments with amino modified dimethylsilicone. Examples cite use of curing temperatures of 100.degree. C.-130.degree. C.
In U.S. Pat. No. 4,020,199 (Nomura, Katsuaki, et. al, Apr. 26, 1977) aminosilicone treatment of acrylic fibers to impart animal hairlike hand is disclosed. The patent specifies that desirable properties are achieved by drying at 60.degree. C.-140.degree. C. but preferably at 80.degree. C.-120.degree. C.
In U.S. Pat. No. 4,020,212 (Erickson, Wayne K) treatment of polyolefin fiber with mixtures of poly(ethyleneoxide) modified silicone and quaternary ammonium salts is reported to reduce scroopiness. Apparently, treatment is applied before crimping, which implies a heat treatment of 80.degree. C.-150.degree. C. Significantly, durability characteristics are not discussed in teachings or examples.
In U.S. Pat. No. 4,054,695 (G. C. Johnson, October, 1977) treatment of synthetic fibers with mixtures of silicones and ethylenediamine tetraacetic acid are reported to yield nonflammable fibers with good lubricity. Examples indicate that a cure at 160.degree. C. is required to effect desirable properties.
In U.S. Pat. No. 4,062,999 (Kondo, Takimitsu, et. al, Dec. 13, 1977) the use of mixtures of aminosilanes and epoxysilicones as a treatment for synthetic fibers used for filling is taught. Examples indicate that best performance was obtained by curing at 140.degree. C.
In U.S. Pat. No. 4,247,592 (Kalinowski, Rober E., January 1981) the use of aminoalkyl containing polydiorganosiloxanes which improves hand of fiberfill without enhancing flammability is taught. Low temperature curing at 50.degree. C.-70.degree. C. effects improvement but examples suggest that best performance is obtained by curing at 107.degree. C.-204.degree. C.
In U.S. Pat. No. 4,388,437 (Ona, Isao, June 14, 1983) the use of titanate, zirconate and germanate compounds with aminofunctional silicones is reported to cause quantitative exhaustion of silicones from mother liquor to substrate surfaces. Examples indicate that curing at 105.degree. C.-150.degree. C. was necessary for best performance. Although fabric properties such as hand, crease resistance and impact resistance was measured, apparently no attempt was made to determine durability.
In Belgium 875-335 (Solomon, Monfred; et. al, Oct. 9, 1979) claims treatment of fiberfill with mixtures of OH terminated dimethysilicone and bisphenol A diglycidyl ether-hexamethylene diamine polymer. Mixture was catalyzed with organotin compounds and cured at 140.degree. C.-200.degree. C. after application to fiberfill.
In Canada 953,058 (Sugiura, Takahisa; et. al, Aug. 20, 1974) the treatment of synthetic fibers with mixtures of dimethylsilicones, aminosilanes, and glycidoxy silanes results in improved hand. Development of desirable properties requires use of zinc 2-ethylhexanoate catalyst and a heat treatment.
In D.E. 2,356,895 (Fujimatsu, Masaski, May 30, 1974) Wool-like properties are imparted to acrylic fibers by treatment with aminomodified silicones. Curing steps of 125.degree. C.-150.degree. C. were specified.
In D.E. 2,449,400 (Betz, Helmut, et. al, Apr. 22, 1976) sequential treatment with poly(ethylene) and then with a mixture of hydroxyterminated dimethylsilicone and methylhydrogen silicone gives desirable fiberfill properties. Finish is applied before crimping with curing effected during crimping.
In Japan Kokai 74,133,698 Sono, Hirofumi, et. al, Dec. 23, 1974) synthetic fibers were treated with mixtures of organopolysiloxanes and aminoalkoxysilane to improve hand. The silicone mixtures were catalyzed with zirconium acetate and cured at 160.degree. C.).